GearmanFrom the Worker's Perspective

/usr/bin/whoami /usr/bin/whoami

Brian AkerBrian Aker

HP FellowHP Fellow

Previously MySQL, Slashdot, Sun Previously MySQL, Slashdot, Sun MicrosystemsMicrosystems

What is Gearman?

“The way I like to think of Gearman is a massively

distributed fork mechanism” -Joe Stump, Digg

“The Not Mechanical Turk” -Don MacAskill, SmugMug

do do (“resize_image(“resize_image”)”)

resize_image()resize_image() {{ … … return $image;return $image;}}

(Livejournal)

Server Provides Asynchronous and Synchronous Provides Asynchronous and Synchronous

RequestsRequests

Restarts WorkRestarts Work

Durable Requests (MySQL, Postgres,...)Durable Requests (MySQL, Postgres,...)

Gearman Protocol/HTTPGearman Protocol/HTTP

Epoch SchedulingEpoch Scheduling

LoggingLogging

(also available, native Servers in Java, (also available, native Servers in Java, Erlang, and Perl)Erlang, and Perl)

Client

# Create our client object.$gmclient= new GearmanClient();# Add default server (localhost).$gmclient->addServer();

$result= $gmclient->do("reverse", "Hello!");echo "Success: $result\n";

Worker

# Create our worker object.$gmw= new GearmanWorker();# Add default server (localhost).$gmw->addServer();

$gmw->addFunction("reverse", "reverse_fn");while ($gmworker->work()) {…}

Worker Function

function reverse_fn($job){ $workload= $job->workload(); $result= strrev($workload); return $result;}

Lots of functions...

$gmw->addFunction("resize", "resize_fn");$gmw->addFunction("grep", "grep_fn");

$gmw->addFunction("fetch_url", "fetch_url");

gearman_return_t fetch_url(gearman_job_st *job, void*){ const char *workload= gearman_job_workload(job); size_t workload_size= gearman_job_workload_size(job); gearman_job_send_status(job, 0, 100);

… gearman_job_send_data(job, chunk, sizeofchunk);

… gearman_job_send_status(job, 50,100);

… if (issue_warning) gearman_job_warning(job, “I'm sorry, Dave. I'm afraid I can't do that.”, size); return GEARMAN_SUCCESS;}

Function

GEARMAN_SUCCESSGEARMAN_SUCCESS

GEARMAN_FATALGEARMAN_FATAL

GEARMAN_ERRORGEARMAN_ERROR

GEARMAN_SHUTDOWNGEARMAN_SHUTDOWN

Worker Return

Client APIClient API(C, PHP, Perl, Python, (C, PHP, Perl, Python,

Java,Drizzle, ...)Java,Drizzle, ...)

Worker APIWorker API(C, PHP, Perl, Python, Java, ...)(C, PHP, Perl, Python, Java, ...)

ServerServer

Your Client Your Client request()request()

Your WorkerYour Workerfunction()function()

Network,Highly Available,Fault Tolerant

Client APIClient API(C, PHP, Perl, Python, (C, PHP, Perl, Python,

Java,Drizzle, ...)Java,Drizzle, ...)

Worker APIWorker API(C, PHP, Perl, Python, Java, ...)(C, PHP, Perl, Python, Java, ...)

ServerServer Provided by Provided by GearmanGearman

Your Client Your Client request()request()

Your WorkerYour Workerfunction()function()

resize_imageresize_image(“…”);(“…”);

resize_image()resize_image(){{ … …;; return resized;return resized;}}

Network,Highly Available,Fault Tolerant

CPU?event()

multiple languages

Connectors?

•C/C++

•PHP

•Python

•Java

•MySQL and Postgres

•....

Other items of interest?

•Work status requests.

•Chunked Data.

•Exception Handling.

•Up to 4gig message sizes.

•Threaded server.

•Coalescence (the stealth killer feature)

NamespacesFoo::resize_image()Foo::resize_image() {{ … … return $image;return $image;}}

Acme::resize_image()Acme::resize_image() {{ … … return $image;return $image;}}

Better Map Reduce?

map(list[…], map(list[…], reduce());reduce());

map() map() {…}{…}

reduce() reduce() {…}{…}

reduce() reduce() {…}{…}

reduce() reduce() {…}{…}

Map @#$@# ?

Partitioning

{A...K}

{L...Q}

{R...Z}

find(find())

find(find())

find(find())

gearman_return_t split_worker(gearman_job_st *job, void* /* context */){ const char *workload= gearman_job_workload(job); size_t workload_size= gearman_job_workload_size(job); const char *chunk_begin= workload; for (size_t x= 0; x < workload_size; x++) { if (workload[x] == 0 or workload[x] == ' ') { gearman_job_send_data(job, chunk_begin, workload +x -chunk_begin); chunk_begin= workload +x +1; } } return GEARMAN_SUCCESS;}

Partitioning

Aggregation

+ result

+ result

+ result$res$resultult

$res$resultult

$res$resultult

= sum result

Aggregation

gearman_return_t cat_aggregator (gearman_aggregator_st *, gearman_task_st *task, gearman_result_st *result){ std::string string_value; do { gearman_result_st *result_ptr= gearman_task_result(task); string_value.append(gearman_result_value(result_ptr), gearman_result_size(result_ptr)); } while ((task= gearman_next(task))); gearman_result_store_value(result, string_value.c_str(), string_value.size()); return GEARMAN_SUCCESS;}

Do we have to partition?

(What other tricks exist!)

Pipeline

Store()Store() Resize()Resize() Publish()Publish()

Future

0.32 Released0.32 Released

Custom Logging PluginsCustom Logging Plugins

Client/Worker Configuration Client/Worker Configuration

Extended Administrative CommandsExtended Administrative Commands

SSLSSL

Status lookup via Unique IdentifierStatus lookup via Unique Identifier

Job Result CacheJob Result Cache

Uplift!Uplift!

•Gearman.org (...)

•http://launchpad.net/gearmand/

•twitter: brianaker

•blog: blog.krow.net

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